I have a 66 350 HP car with a Holley 4160 carburetor that has a strange fuel leak. It does not leak while running and will not leak after you shut it off for up to 18 hours. It then leaks fuel from the secondary shaft on the passenger side just to the left of the choke coil. I can not figure where it gets it source of fuel on this side this long after it runs. Have checked and found intake manifold to be warm to the touch almost up to the time it starts leaking. I assume it has to be thermal expansion and contraction of the shaft/bushing or vaporization of fuel in the secondary bowls and accumulation on the back barrels. Except for this the carburetor runs fine except hard to start after sitting a week or longer. Almost like it is out of fuel then flooded. Any help is appreciated.